Wire spring pushbutton assembly



Sept- 7 1965 F. T. BlLx-:K 3,205,318

WIRE SPRING PUSHBUTTON ASSEMBLY Filed June 11, 1963 7/ CIEJD CIDE! DDD o 46 nucl non uuu ,IQJAL est, CI D El El CI D DDD 111111111111111111111111110 4f 4 52 aan DDD nun 4 L4 DDD DDC! DDD DDD DDD DDD 3 El D DDD 2l 70 CID CID .V CIDEI DDD DDD DEICI DDD DDD FIG 4 FIG 5 INVENTOR.

ATTORNEY United States Patent O 3,205,318 WIRE SPRING PUSHBUTTGN ASSEMBLY Frank Thomas Bilek, Downers Grove, Ill., assigner to International Telephone and Telegraph Corporation, a corporation of Maryland Filed June 11, 1963, Ser. No. 287,049 9 Claims. (Cl. 200-5) This invention relates to wire spring pushbutton assemblies, and more particularly to the coded crosspoint type of assemblies.

Pushbutton assemblies are used on a number of machines such as adding machines, telephones, and control consoles for automobile machine tools. One way of using these pushbuttons is to extend a wire from every button to a storage element which contains means for indicating a particular numerical value. This runs into expensive cabling and requires a wasteful duplication of storage elements. Thus, it is common practice to use coded cornbinations of signals for designating the numerical value of the individual pushbuttons. For example, the numerical value one could be indicated by simultaneously marking wires l and 2 of a five wire cable; two could beY indicated by marking wires l and 3, etc.

Heretofore, to provide such coded combinations, pushbutton assemblies have been manufactured as crosspoint devices. That is, the pushbutton assembly selectively controls the application of electrical potentials to the crosspoints of a matrix of horizontal and vertical multiples. If, for example, a button is pushed at the intersection of a tirst horizontal and a tirst vertical multiple, those two multiples are marked to indicate the numerical value onef If the pushed button is located at the intersection of the rst horizontal and second vertical multiples, those multiples are marked, perhaps to indicate a two. In like manner, if pushed, every other pushbutton causes the multiples at its associated intersection to be marked. l The problem'with these assemblies has been primarily one of utilizing the mechanical pushbutton motion to provide corresponding electrical markings because this has required expensive and complex linkages.

Accordingly, an object of the invention is to provide new and improved pushbutton assemblies.

Another object is to provide crosspoint type pushbutton assemblies for giving coded outputA signals. Here an object is to provide such assemblies without requiring complex mechanical linkages. j

Yet another object is to provide assemblies which may be constructed easily and economically on standard machinetools. More specifically, an object is to provide standard size pushbutton assembly modules which may be ganged together to enlarge or reduce the number of pushbuttons in an assembly requiring special size piece parts.

In accordance with one aspect of the invention, these and other objects are accomplished by pushbutton assemblies which translates downward pushbutton motion into longitudinal mechanical motion. The assembly comprises a base plate having a coordinate grid of horizontal and vertical guideways formed therein. Positioned in each guideway is a wire spring having a wave like configuration, preferably a sinusoidal wave form. The crests of the spring waves appear at the intersections of the guideways. A pushbutton is positioned immediately above each intersection and freely rests upon the crests of the spring waves. Thus, if any pushbutton is pressed down, the crest of the wire spring is forced down. This causes the spring to stretch out, thus providing a longitudinal motion. A snap action switch, positioned at the end of each guideway, responds to this longitudinal motion to provide electrical output signals.

Other objects and features of this invention will become "lee apparent and the invention will be best understood when the specification is read in conjunction with the accompanying drawings comprising FIGS. 1 to 5 in which:

FIG. l shows (in perspective view) a fragment of a machine incorporating a pushbutton assembly constructed in accordance with this invention;

FIG. 2 is an exploded view of the pushbutton assembly;

FIG. 3 is a cross-section view (taken along lines 3--3 of FIG. 2) which illustrates an exemplary wire spring having a sinusoidal wave form, the spring being tted into a guideway formed in the base plate;

FIG. 4 is a View of a cross-section fragment of the base plate (taken along line 4--4 of FIG. 3) which illustrates how a snap feel is given to the pushbuttons; and

FIG. 5 shows how a number of pushbutton assemblies may be joined together to provide an enlarged key board console.

The machine of FIG. 1 may have many different forms; it could be an adding machine, a telephone, a machine tool control panel, or the like. As here shown, the machine has ten pushbuttons to provide single decade. If it should be desirable to provide additional decades, it is only necessary to duplicate the entire assembly.

The pushbutton assembly is of the crosspoint type.`

That is, each pushbutton is located at an intersection of a horizontal row and a vertical column. Thus, if any pushbutton is pushed down, an electrical marking appears at both a row and a column output. Since three rows and three columns are shown, this means that each pushbutton could send up to a two-out-of-six code.

In keeping with one aspect of the invention, the push-v button assembly may be fabricated as shown in FIG. 2. This assembly is made from a base plate 20 adapted to support wire, such as 21, and a cover plate 22. While these plates may be` made of any suitable material, the invention contemplates the use of a material, such as Bakelite or nylon. The dot-dashed lines (such as L1) indicate that the cover plate 22 tits over and is secured to the base plate 20.

Preferably the base plate is molded to have a coordinate array of intersecting guideways. Arrst plurality of` guideways 23-25 are here shown as having a horizontal orientation and a second plurality 26-28 as having a vertical orientation. Thus, a coordinate grid pattern is formed by the guideways. At each intersection (such as 30), the lmaterial has a cavity formed therein to receive and guide a pushbutton base. Thus a pushbutton 31 may slide up and down in the cavity 30, guided by the sidewalls thereof.

Positioned above the base plate 20 is the cover plate 22 having a, number of openings therein. One such opening is shown at 40. The openings are positioned so that each coincides with and is immediately above an intersection of two of the guideways 2348. Each opening is shaped and dimensioned to receive the top of a pushbutton. For example, the top ofthe pushbutton 31 slides in and is guided by the opening 40.

The dimensions of the guideways 23-28 are such that each receives and supports a wire spring having a predetermined wave form. For example, the spring 41 tits into the guideway 25, and the spring 42 fits into the guideway 26. The vertical axis of the Wave form is perpedicu' piano wire which is cut off at the desired length, as used. Or, the piano wire could be shaped to specific lengths before the heat treatment. The choice is one of economics.

In any event, the final length of the wire spring is selected to coincide with the length of the guideways 23-28. As shown in FIG. 3, one end 44 of the wire spring is attached to the base plate, and the other end 45 projects beyond the base plate. This way the projecting end 45 of the wire spring must slide out of the base plate if the spring is stretched. Conversely, the end 45 of the wire spring retracts into the base plate if the spring shortens. To utilize this lateral motion for providing electrical signals, a small snap action switch is positioned adjacent each spring end 45 that projects from the base plate. For example, two such switches are shown at 46, 47. Four other switches, not shown, are located at 4S, 49.

By inspection of the drawing, it should be apaprent that the spacings between the guideways are such that the crests of the wire spring wave forms appear at the intersections of the guideways. The valleys of the wave forms appear between the intersections. Thus, in FIG. 3, a crest 50 appears at intersection 51, and a valley 52 appears between intersections 51, 53.

Prefrably each pushbutton is a unitary piecepart molded from Bakelite, nylon, or a similar material. The general configuration of such a pushbutton should be ,apparent from a study of the exemplary pushbutton 31. This configuration comprises a shank portion 60 terminated at the lower end in a plate or ilange section 6l. The shank portion 60 has a cross section which generally fits -into the holes (such as 40) of the cover plate. The flange portion 61 has a cross section which generally fits into the holes at the intersections of the guideways in the base plate. This way, the pushbutton is guided as it slides up and down.

The bottom of each pushbutton flange has two grooves generally disposed at right angles to each other. The crest of a horizontally disposed wire spring rides in one groove 63 and the crest of a vertically disposed wire spring rides in the other groove 64. This way the tension of two wire springs normally urges the pushbotton upward to a position where the flange 61 bears against the cover plate 22. Also, the two springs give a two point support to the pushbutton to provide greater mechanical stability.

If a pushbutton is pushed down, each of the intersecting wire springs is deformed at its crest. This moves the spring valley longitudinally toward the free end 45. As shown by dotted lines at 66, the entire spring slides to the right. This longitudinal motion operates the small snap action switch 46 positioned at the end of the wire spring. For example, an actuation arm of the switch 46 is shown as extended to an operated position at 66. When the pushbutton is released, the wire spring tension causes it to raise.

To provide a feel or -a snap action, the walls of the guideways are molded with projections 7@ (FIG. 4) which the wire springs must pass as they are deformed by downward pushbutton action. As each spring passes the projection, it snaps. Thus, the finger pushing the button can feel the snap, and the person pushing the button receives a psychological effect of doing something. The pushbutton actually stops its downward motion when the -ange 61 bottoms in the recess 30.

The foregoing has been a description of a single pushbutton assembly which can serve as a building block, or a module for a larger assembly. As shown in FIG. 5, a number of these identical modules may be bolted together in a side-by-side relation to increase the number of pushbuttons. For example, one such module is shown at 71 (FIG. 5). If the wire spring is made in a continuous I length, it is only necessary to cut it to the total length of iall of the base plates which are bolted together. For example, FIG. 5 shows a 3 X 3 assembly, so each spring is long enough to pass through three base plates. If the springs are formed on a custom basis they will prefrably be shaped to provide a number of stock lengths which iit say two, three and four base plates.

While l have described my invention in conjunction with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation on the scope of the invention.

I claim:

1. A pushbutton lassembly comprising a base plate having a cordinate array of intersecting horizontal and vertical guideways formed therein, a plurality of pushbuttons, means comprising an elongated undulating spring in each of said guideways for biasing said pushbuttons to a normal position and for translating downward motion at any of said intersections linto longitudinal motion along the length of said guideways, and means at the end of each of said guideways operated responsive to said longitudinal motion of said spring for providing electrical output signals.

2. The assembly of claim 1 and means for providing a snap feel when a pushbutton is depressed.

3. The assembly of claim 2 wherein each of said guideway springs comprises a wire spring having a general sinusoidal wave form.

4. The assembly of claim 3 wherein said pushbuttons being positioned to bear downward upon said wire springs at the crests of said wave forms in said guideways.

5. A pushbutton assembly comprising a base plate having a cordinate array of intersecting horizontal and vertical guideways formed therein, translating means in each of said guideways comprises a wire spring having a general sinusoidal wave form for translating downward motion at any intersection of a horizontal and vertical guideway into longitudinal motion along the length of each of said intersecting guideways, and means at the ends of said guideways responsive to said longitudinal motion for providing electrical output signals.

6. The assembly of claim 5 and a plurality of pushbuttons, each of said pushbuttons being positioned to bear down upon a pair of said wire springs at the crests of said wave forms, said crests being located at intersections of said guideways, thereby distorting said wave form and stretching said spring.

7. The assembly of claim 6 wherein each of said motion to signal providing means comprises a small snap action switch.

8. The assembly of claim 6 and cover plate positioned above said base plate each of said pushbuttons comprising a unitary structure riding in openings in said cover and base plates.

9. The assembly of claim 5 and means for ganging a plurality of said assemblies as building blocks for larger pushbutton assemblies, said ganging means comprising long ones of said sinusoidal springs extending through longitudinally aligned guideways in a plurality of said base plates.

References Cited by the Examiner UNITED STATES PATENTS 1,528,761 3/25 Goi.

2,320,774 6/43 Flynt 200-5 2,507,381 5/50 Morse 200-166 3,120,584 2/ 64 Grunfelder 2005 KATHLEEN H. CLAFFY, Primary Examiner.

BERNARD A. GILHEANY, Examiner. 

1. A PUSHBUTTON ASSEMBLY COMPRISING A BASE PLATE HAVIN A CORDINATE ARRAY OF INTERSECTING HORIZONTAL AND VERTICAL GUIDEWAYS FORMED THEREIN, A PLURALITY OF PUSHBUTTONS, MEANS COMPRISING AN ELONGATED UNDULATING SPRING IN EACH OF SAID GUIDEWAYS FOR BIASING SAID PUSHBUTTONS TO A NORMAL POSITION AND FOR TRANSLATING DOWNWARD MOTION AT ANY OF SAID INTERSECTIONS INTO LONGITUDINAL MOTION ALONG THE LENGTH OF SAID GUIDEWAYS, AND MEANS AT THE END OF EACH 